One difference: Thomas Aquinas calls the light of grace "created", though he does not try to prove that point, he only argues that it is needed a light that exceeds all merely human light.
Another: he believes that the blessed in Heaven see the very essence of God, not just his energies. This is the one point where Rome actually condemned the fifth council of Constantinople ... apparently agreeing by implication that Barlaam was condemnable.
A pseudo-difference: Aquinas says that what is illumined by grace is our intellect. Later misuse of the word has made him being misunderstood as meaning "the ability to argue". To Thomas the ability to argue is only a very secondary side of intellect. Rationality is an imperfection of intellect, as compared with intuitive intellect. To him intellect means "that which understands", i e what the Greek language calls nous.
A convention: before saying what he thinks, he always leaves the word, so to speak, to his adversaries - or rather to what they would say and quote for themselves.